1. Field of the Invention
The present invention relates to an apparatus for treating an end portion of a sewing thread supplied from a thread supplying device of a sewing machine.
2. Related Art Statement
There is known a sewing machine having a threading device. Before commencement of sewing operation of the sewing machine, a needle thread is drawn from a thread supplying device by a user, and an end portion of the thread is put through an eye hole of a sewing needle by the threading device. While the thread end is pulled and tensioned, the needle is moved down and up to draw a bobbin thread from a bobbin. The needle and bobbin threads are placed side by side and conveyed to a thread cutter provided on a cover member of a sewing head or a throat plate having a throat through which the needle is moved vertically.
An example of the above-indicated thread-end treating device is disclosed in Unexamined Japanese Patent Application laid open for inspection under Publication No. 3(1991)-133484. The disclosed device treats, before commencement of a sewing operation of a sewing machine including a threading device which puts a sewing thread through an eye hole of a sewing needle, an end portion of the sewing thread so that a predetermined length of the thread is drawn out through the needle eye. The prior device includes (a) a guiding device which guides, along a thread-guiding route passing near the sewing needle, the sewing thread supplied from a thread supplying device before the commencement of the sewing operation of the sewing machine, the guiding device including a guiding member which is provided in the thread-guiding route and which engages the sewing thread supplied from the thread supplying device; (b) an intermediate holding device which is provided on a downstream side of the guiding member in the thread-guiding route and which holds the sewing thread with a biasing force applied substantially perpendicularly to the thread-guiding route; and (c) a cutting device which is provided on a downstream side of the intermediate holding device in the thread-guiding route and which cuts off an excessive length of the end portion of the sewing thread held by the intermediate holding device, at a position distant by a predetermined distance from the guiding member in the thread-guiding route. The guiding member is movable toward the sewing needle to stretch a portion of the sewing thread in front of the needle eye, so that the sewing thread is put through the needle eye by the threading device of the sewing machine.
The thread-end treating operation of the above-identified thread-end treating device is described below by reference to FIGS. 7A and 7B. Before commencement of the sewing operation, a user picks up an end of a sewing thread T drawn from a thread supplying device (not shown), and stretches the thread T along a thread guiding route 101, 103 such that first the thread T is engaged with a thread engaging device 105 and subsequently is held by a movable holding device 107. The movable holding device 107 holds the thread T with a holding force applied substantially perpendicular to the thread guiding route. After the sewing thread T is further guided downstream along the thread guiding route 101, 103, the thread T is tensioned and an excessive length of the thread T is cut off on a thread cutting device 109 which is provided at a position distant by a predetermined distance from the thread engaging device 105 in the thread guiding route. In order to put the sewing thread T through an eye hole 199 of a sewing needle 197, the thread engaging device 105 with which the thread T is engaged is moved toward, and stopped adjacent, the needle eye 199. In this state, the thread engaging device 105 and the movable holding device 107 are distant from each other by a predetermined distance. Therefore, a predetermined length of the thread T is obtained between the cut end thereof and the thread engaging device 105 positioned adjacent to the needle eye 199. Accordingly, the predetermined length of thread T can be drawn out through the needle eye 199.
However, in the prior device, the thread cutting device 107 is provided in the back of a sewing head 117, as shown in FIG. 7B. Thus, the user who faces a front surface of the sewing head 117 cannot cut the sewing thread T while actually viewing the thread end T and the cutting device 109. The user must move around to the back of the sewing machine or otherwise feel his or her way to cut the thread T on the cutting device 109. Accordingly, the reliability and operability of the prior device are not satisfactory.